I just put my suggested method in a SLC5/05 (mo PLC 5's laying around in my house)
Using 4 timers, 0.01 base, presets of 6, 4, 5, & 3, each triggering a counter PRE 50.
I used integer file N12 and put random numbers 0 - 9 from N12:0 to N12:51. I entered them blindly without looking at the keypad then checked for double digit numbers and changed them to only the first digit.
Using a 5th 0.01 timer with a PRE of 100 for 1 second I triggered my CPT instruction.
Logging the results in Excel through AdvancedHMI/EPPS I let it run for a few minutes. The resulting numbers show no obvious pattern, range from 104 to 9638, and had no duplicate numbers when I sorted the Excel data.
Going to let it run and see how many of the 65,000 rows I can fill then look through it when I get a couple days.
As far as any real need for a random number generator not using a dedicated supercomputer I think this should be good enough.